Need advice....
09-19-2003, 09:14 AM
#1
50 Watt CAFz'r
Thread Starter
Join Date: Jun 2003
Posts: 372
I have a 15" PG Xmax I bought from MrMarco (hell of a guy!) anyway, I'll be running it off of a Kicker KX400.2 that puts out 484 watts. I want it to have clear tight bass but also to get loud. PG reccomends 3 cubes tuned to 38 hertz. That seems to be tuned a little high. I was thinking around 3 cubes tuned to 28. What do you guys think? I have never owned a 15 before and am not sure what to tune it to in order to maximize the SQ. Thanks for any help. [img]smile.gif[/img]
09-19-2003, 11:11 AM
#2
1000 Watt CAFz'r
Join Date: May 2002
Posts: 1,649
Dukk is the expert here on porting........and I may be way off as it's been a while.
First, why do you think 38hz is too high????
Likely the manufacturer's specs give you a fairly flat curve with "maybe" a mild bump in the lower end. The lower you push that tuning frequency, the greater the bump may grow but further down the frequency spectrum of course. This also causes the curve to no longer remain flat as you travel up the frequency spectrum where it use to be flat according to the original design. You'll get a drop in frequency response where the curve use to be flat.
It's possible that PG did the design for an in-car response as well, but every car is different. You may be able to lower the tuning frequency and come off golden, but that's just speculation on my part. And just so you know, tuning down at 38 hz is pretty low. IF I was you, I'd build it according to manufacturer's specs........ assuming they properly designed the box. BTW, I have no experience with PG box designs so I can't accuractely speak on behalf of their box designs.
[ September 19, 2003, 12:13 PM: Message edited by: dawgsbreakfast ]
First, why do you think 38hz is too high????
Likely the manufacturer's specs give you a fairly flat curve with "maybe" a mild bump in the lower end. The lower you push that tuning frequency, the greater the bump may grow but further down the frequency spectrum of course. This also causes the curve to no longer remain flat as you travel up the frequency spectrum where it use to be flat according to the original design. You'll get a drop in frequency response where the curve use to be flat.
It's possible that PG did the design for an in-car response as well, but every car is different. You may be able to lower the tuning frequency and come off golden, but that's just speculation on my part. And just so you know, tuning down at 38 hz is pretty low. IF I was you, I'd build it according to manufacturer's specs........ assuming they properly designed the box. BTW, I have no experience with PG box designs so I can't accuractely speak on behalf of their box designs.
[ September 19, 2003, 12:13 PM: Message edited by: dawgsbreakfast ]
09-19-2003, 12:56 PM
#3
Guest
Posts: n/a
^ Everything Tom said is for sure on the money.
IMO 38hz may be a little high for a 15 but then the XMax was meant to be LOUD right - so that is probably where they were heading.
I generally tune most boxes in the 35hx range which really isn't much lower than the recommended 38hz. 15s I will usually tune lower though just to kill off the immense midbass output they will give off. I never drop below 30hz though and really, day to day, you may never even notice the difference between 30 and 38hz - I mean we are talking a fraction of an octave.. [img]graemlins/dunno.gif[/img]
IMO 38hz may be a little high for a 15 but then the XMax was meant to be LOUD right - so that is probably where they were heading.
I generally tune most boxes in the 35hx range which really isn't much lower than the recommended 38hz. 15s I will usually tune lower though just to kill off the immense midbass output they will give off. I never drop below 30hz though and really, day to day, you may never even notice the difference between 30 and 38hz - I mean we are talking a fraction of an octave.. [img]graemlins/dunno.gif[/img]
09-19-2003, 07:21 PM
#7
50 Watt CAFz'r
Thread Starter
Join Date: Jun 2003
Posts: 372
Originally posted by pat28ca:
for xmax15
sq sealed is 2.0 cub ft .
sq vented is 3.0 tuned to 28hz. 4 inch port 10 inches long.
spl are 1.5 sealed and 2.0 with a 4x10 inch port
for xmax15
sq sealed is 2.0 cub ft .
sq vented is 3.0 tuned to 28hz. 4 inch port 10 inches long.
spl are 1.5 sealed and 2.0 with a 4x10 inch port
[ September 19, 2003, 08:22 PM: Message edited by: Gettnbig ]
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